This circuit was found in Radio Electronics from the 90s. It converts capacitance into frequency in order to obtain a proportional voltage that can be measured in a common multimeter.
Only incandescent lamp can be used in this circuit. The SCR must be mounted on a heatsink and...
This circuit originally appeared in a publication of 1997. With the changes, the circuit can be...
This circuit is from a 1969 Electronics World. The transistors may be modern general-purpose...